1. Field of the Invention
The present invention relates to a counter substrate for liquid crystal display and a liquid crystal display device.
2. Description of the Related Art
A general liquid crystal display device includes a liquid crystal cell in which a liquid crystal layer is sandwiched by transparent substrates such as glass substrates. Additionally, the general liquid crystal display device includes a liquid crystal panel. In the liquid crystal panel, a polarizing plate and a retardation plate are provided above/on a surface and back surface of this liquid crystal cell. For example, a liquid crystal display device having a structure in which a back light is disposed as a light source at a back surface opposite to an observer, or a liquid crystal display device utilizing an external light source such as a room light in addition to a back light, is utilized. The liquid crystal display device utilizing the external light source includes the liquid crystal panel containing the polarizing plate and the like with the liquid crystal cell. In a three-dimensional liquid crystal display device (stereoscopic image liquid crystal display device) and a view angle controlling liquid crystal display device, the liquid crystal panel utilizing the back light or external light source controls an outgoing angle of an outgoing light from a surface of the liquid crystal panel according to a display purpose.
Various systems are known as the three-dimensional liquid crystal display device or three-dimensional display. These systems may include a system utilizing glasses and a system utilizing no glasses. A system utilizing specific glasses such as an anaglyph system utilizing a color difference or a polarized glasses system utilizing polarization of light may have troublesomeness because the observer have to wear glasses when the observer watches a three-dimensional image. Recently, a demand for a system which does not require wearing glasses is increasing.
In order to control the angle of the light from the liquid crystal panel surface and output the light to the single observer or multiple observers (hereinafter it may be referred to as “binocular” or “multiocular”), a technique of the liquid crystal display device including a light-controlling element for a surface or back surface of the liquid crystal panel, is used.
The light-controlling element used in the three-dimensional liquid crystal display device which does not require wearing glasses is generally divided into three systems.
A first system is a lenticular lens system which two-dimensionally arranging optical lenses to utilize regular refraction. The lenticular lens is formed from a transparent resin into a sheet, and is used by pasting it to a surface or back surface of the display device. Patent Document 1 (Japanese Patent No. 4010564) and Patent Document 2 (Japanese Patent No. 4213226) disclose three-dimensional image display techniques using a lenticular lens (lenticular screen).
A second system is a parallax barrier system which two-dimensionally arranges light-shielding slits, called as a parallax barrier, in one direction, and obtain outgoing lights for a right eye and a left eye by utilizing the arrangement. Patent Document 3 (Jpn. Pat. Appln. KOKAI Publication No. 2007-11254), Patent Document 4 (Jpn. Pat. Appln. KOKAI Publication No. 2009-139947) and Patent Document 5 (Jpn. Pat. Appln. KOKAI Publication No. 2010-210982) disclose the three-dimensional image display technique using the parallax barrier.
A third system is a flexible lens array system which controls the outgoing light concerned with a three-dimensional image using an optical element. In the optical element, index of refraction or phase axis is changeable by application of a voltage, or the like. For example, the optical element is a liquid crystal, a ferroelectric piezoelectric element, or the like. Patent Document 6 (Jpn. Pat. Appln. KOKAI Publication No. 2000-102038) and Patent Document 7 (Japanese Patent No. 3940725) disclose techniques using a liquid crystal lens array.
The parallax barrier system uses the light-shielding slits, and accordingly has a defect of decreasing light transmittance. In addition, according to the parallax barrier system, a non-display region which includes the light-shielding slits, interferes an observation by the observer, when the position of the observer is not appropriate, whereby an area in which the three-dimensional image cannot be observed may become wider.
In the lenticular lens system and the flexible lens array system, the defect of decreasing light transmittance occurring in the parallax barrier system is reduced. In the case of a cell phone or game machine including a compact liquid crystal panel used by the single observer (binocular), however, the liquid crystal panel tends to be thick and heavy in both of the systems.
In addition, the lenticular lens system shown in Patent Documents 1 and 2 described above employs a technique for collecting multiple units (unit pixels) and displaying by one lens for realizing the three-dimensional display function. The multiple units includes N units which are adjacent. N is more than 2. In a case of a full-color display, a unit (unit pixel) is generally composed of three color pixels of a red pixel, a green pixel and a blue pixel. Accordingly, a resolution of the liquid crystal display is greatly reduced, and further it is difficult to switch between the two-dimensional display (general display) and the three-dimensional display.